Nonaqueous-electrolyte secondary battery and method of manufacturing the same

ABSTRACT

To offer excellent hermeticity inside a battery having high productivity and being covered with package members by means of solving a problem such as sealing failures caused by gaps between sides of lead electrodes and the package members in sealing parts, in which the lead electrode to be disposed. During a step of sealing between ends of the package members and the lead electrodes by fusing the sealing members, or during a step of adhering the fused sealing members to the lead electrodes, stripping sheets made of a material such that the fused sealing members does not adhere to heaters, are inserted between the package members, or the sealing members and the heaters. Accordingly, even if the fused sealing members are forced out from ends of the package members, or leaked toward the outside, the sealing members does not adhere to surfaces of the heaters or crumble their shapes.

RELATED APPLICATION DATA

[0001] The present application claims priority to Japanese ApplicationNo. P2000-081578 filed Mar. 23, 2000, which application is incorporatedherein by reference to the extent permitted by law.

BACKGROUND OF THE INVENTION

[0002] The present invention relates to a lithium ion battery such as alithium ion polymer secondary battery having a gel-type or plasticmacromolecular electrolyte layer, and a method of manufacturing thesame.

[0003] In recent years, accompanying by a situation that portable smallelectric equipment such as small, lightweight cellular phones orportable computers has been popularized, second batteries having small,reliable output characteristics and capable of longtime use byrecharging many times such as nickel-cadmium batteries, nickel-hydrogenbatteries and lithium ion batteries has been studied and developedvastly as an electric source for supplying electric power to drive theelectric equipment.

[0004] Among the secondary batteries, the lithium ion secondary batteryhas characteristics capable of outputting stable electric power despiteits small, lightweight, thin in size, and has studied and developed forthe purpose of employing a s a foldable secondary battery by takingadvantage of suitable structural characteristics for its thin size.

[0005] Further, as technique capable of achieving the above-mentionedthin size and foldable shape, and of gaining superior characteristicsfree of leakage unlike the case of employing liquid electrolyte as a drycell, it is suggested that a technique employs gel-type electrolyteincluding plasticizer realizing flexibility, and a technique employsmacromolecular solid electrolyte, in which a lithium salt is dissolvedin a macromolecular material.

[0006] In such lithium ion secondary batteries with a thin structure,generally, the main part of the battery is formed in the followingmanner. A laminating structure is formed by laminating a positiveelectrode, a positive electrode active material layer, a gel-typemacromolecular solid electrolyte layer, a separator, a negativeelectrode, a negative electrode active material layer. A positiveelectrode lead and a negative lead electrode joints to the correspondingelectrodes in the laminating structure. After this, the laminatingstructure is covered with package members made ofaluminum/polypropylene•laminate pack material, and sealed ends.

[0007] As for materials used for the above-mentioned schematicstructure, for instance, materials described later can be preferablyused. Plastic materials employed here are shortened hereinafter:polyethylene terephthalate;PET, fused polypropylene;PP, castpolypropylene;CPP, polyethylene;PE, low-density polyethylene;LDPE,high-density polyethylene;HDPE, linear low-density polyethylene;LLDPE,nyron;Ny. Additionally, aluminum, which is a metal material employed asa barrier film having moisture permeability resistance, is shorten asAL.

[0008] The most typical structure is a combination such that a packagemember, a metal film and a sealant layer are respectively PET, AL, andPE. Other typical laminating structures can be also employed as the sameas this combination. Such combinations are:PET/AL/CPP, PET/AL/PET/CPP,PET/Ny/AL/CPP, PET/Ny/AL/Ny/CPP, PET/Ny/AL/Ny/PE, Ny/PE/AL/LLDPE,PET/PE/AL/PET/LDPE, or PET/Ny/AL/LDPE/CPP.

[0009] As for materials employed as the sealant layer of a laminatingfilm, the above-exemplified PE, LDPE, HDPE, LLDPE, PP, and CPP and thelike can be employed, and its thickness is preferably in a range of 20μm˜100 μm based on the observed results. The fusion temperature of thematerials employed as the sealant layer are generally hereinafter. Thefusion temperature of PE, LDPE, HDPE and LLDPE are within a range of120-150° C., that of PP and CPP are about 180° C., and the fusiontemperature of PET employed as the package layer is over 230° C.

[0010] As materials employed as a barrier film having moisturepermeability resistance, although aluminum is exemplified in the aboveexample, it is not limited, and materials capable of forming thin filmsby means of sputtering can be employed. As for such materials, alumina(Al₂O₃), silicon oxide (SiO₂), and silicon nitride (SiNx) can beemployed.

[0011] In a conventional means for sealing the ends of the packagemembers of the lithium ion secondary battery with a thin structure,generally, adhesive material with high adhesion for the metal materialand the package members of the lead electrodes, is applied on a positionwhere the ends of the package members are sealed, and pressure isapplied on the position to be sealed. In another means, the adhesivematerial is only applied to surfaces of the sealed positions in each ofthe lead electrodes and the ends of the package members are appliedpressure to each of the lead electrodes so as to seal the part.

[0012] However, in the conventional sealing structure and method ofmanufacturing the same using the adhesive material as described above,there are problems such that even if the package members can becompletely sealed to principal surfaces of the lead electrodes, gaps areeasy to be produced between sides of the lead electrodes and the packagemembers, which causes an incomplete sealing state (or hermeticitydecrease), thereby, insides of the batteries are susceptible toinfluence of temperature variations or influence from the outside, andby secular change in the batteries, the insides of the batteriesdeteriorates rapidly, which results in decrease of electromotive forceand reduction of durability. Additionally, such batteries occurred thegaps causing degradation of battery capability, must be treated as anonconforming battery, which results in productivity decrease.

SUMMARY OF THE INVENTION

[0013] The invention has been achieved in consideration of the aboveproblems and its object is to provide a lithium ion battery with highproductivity and excellent in hermeticity inside the battery coveredwith a package member by means of preventing sealing failures caused bya gap occurred between sides of a lead electrode and the package member,and a method of manufacturing the same.

[0014] A nonaqueous-electrolyte secondary battery according to thepresent invention comprises a laminating structure, in which at least apositive electrode and a negative electrode are laminated, a film-likeor sheet-like package member for covering the laminating structure, alead electrode whose one end joints to the laminating structure and theother end protrudes toward the outside from an end of the packagemember, and a sealing member, which is inserted between the end of thepackage member and the lead electrode by fusing a thermoplasticmaterial, and seals the gap therebetween.

[0015] In a method of manufacturing a nonaqueous-electrolyte secondarybattery according to the present invention, a step of sealing a gapbetween a lead electrode and an end of a package member, whereby asealing member made of a thermoplastic material is inserted between thelead electrode and the end of the package member, wherein the electrodewhose one end connects to the laminating structure and the other endprotrudes from the end of the package member toward the outside, and thesealing member fuses in order to seal the gap therebetween.

[0016] Further, a method of manufacturing another nonaqueous-electrolytesecondary battery according to the present invention comprises a step ofsealing a gap between a lead electrode and an end of a package member,whereby a sealing member made of a thermoplastic material is insertedbetween a lead electrode and the end of the package member, wherein theelectrode whose one end joints to a laminating structure and the otherend protrudes from an end of a package member toward the outside, aheater is applied to heat to the ends of the sealing member for fusionat temperature over its fusion temperature from the outer side.

[0017] Further more, a method of manufacturing anothernonaqueous-electrolyte secondary battery according to the presentinvention comprises a step of sealing a gap between a lead electrode andan end of a package member, whereby the sealing member made of athermoplastic material is inserted between the end of the package memberand the lead electrode whose one end joints to the laminating structureand the other end protrudes from the end of the package member towardthe outside, a heater is applied pressure to at least the end of thepackage member from the outside, a stripping sheet made of a materialsuch that at least its surface does not adhere to the sealing member, isinserted, then the heater is generated heating to the sealing member attemperature over its fusion temperature for fusion.

[0018] A method of manufacturing another nonaqueous-electrolytesecondary battery according to the present invention comprises steps offusing a sealing member, whereby the sealing member is inserted betweena lead electrode whose one end joints to the laminating structure, andthe other end protrudes from an end of the package member, at leastpressure is applied to the end of the package member from the outside, astripping sheet made of a material such that at least its surface doesnot adhere to a sealing member, is inserted between a heater and thepackage member, or the sealing member, and of separating the strippingsheet from the package member, or the sealing member whereby after thesealing member can spread between the lead electrode and the packagemember without a gap after heating and fusing the sealing member, thestripping sheet is separated from the heater, then the fused sealingmember re-solidifies to be made in a solid state.

[0019] A method of manufacturing another nonaqueous-electrolyte batteryaccording to the present invention comprises steps of fusing a sealingmember, whereby the sealing member made of a thermoplastic material isdisposed in a predetermined position of a lead electrode, pressure isapplied to at least the sealing member from the outside, a strippingsheet made of a material such that at least its surface does not adhereto the sealing member, is inserted between the heater and the sealingmember, and of separating the stripping sheet from the package member,whereby after sealing member can spread between the lead electrode andthe package member without a gap by heating and fusing the sealingmember, the stripping sheet is separated from the heater, then after thefused sealing member re-solidifies to be made in a solid state.

[0020] In a nonaqueous-electrolyte secondary battery and a method ofmanufacturing the same, since a sealing member made of a thermoplasticmaterial is fused and inserted between an end of a package member and alead electrode for sealing a gap, the sealing member can spreadtherebetween. Since the sealing member adhere to the lead electrode byfusing the sealing member, the sealing member adhere to the leadelectrode without a gap.

[0021] In a method of manufacturing a nonaqueous-electrolyte secondarybattery according to the present invention, during a step of sealing agap between an end of a package member and a lead electrode by fusingand inserting a sealing member, since a stripping sheet made of amaterial such that at least its surface does not adhere to the sealingmember, is inserted into the package member or the sealing member andthe heater, the heater is applied pressure and generated heating to thepackage member or the sealing member, even if the fused sealing memberis leaked or forced out from the end of the package member toward theoutside, it does not adhere to a surface of the heater.

[0022] Additionally, since the stripping sheet has a sheet-like shapeunlike the case it is annexed to the surface of the heater in a flatshape, the heater presses the stripping sheet in a manner of shapingalong with a concave-convex shape of the sealing member, thereby, evenif after the sealing member fuses and spreads between the packagemember, the package member and the sealing member are soon stripped fromthe heater with the stripping sheet, the shape of the sealing member andthe state of the lead electrode can be maintained until the sealingmember re-solidifies to be made in a solid state.

[0023] For this reason, without letting the heater is repeated to heatand cool itself, when heating generated is necessary, the heater pressedthe package member and the sealing member in order to fuse the sealingmember, then on the sealing member fuses enough, the heater is separatedfrom the package member covered with the stripping sheet and the sealingmember, which gives the time when the sealing member cools andre-solidifies at room temperature, or by forced cooling wind. This alsomaintains the shape of the sealing member even if the heater is apartwhen the sealing member does not solidify yet. From this point, thestripping sheet is desirable used in a sheet-like state, which can beseparated from the heater rather than coating on the surface of theheater.

[0024] In the case that the above-mentioned lithium ion battery is asolid electrolyte battery, or gel-type electrolyte gel, as amacromolecule material employed for macromolecular solid electrolyte,silicon gel, acryl gel, acrylonitrite gel, polyphosphazen denaturedpolymer, polyethylene oxide, polypropylene oxide, and composite polymerof the above-mentioned materials, cross-linked polymer of theabove-mentioned materials, denatured polymer of the above-mentionedmaterials can be employed, as for fluorine polymer, for example,poly(vinylidenefluororide),poly(vinylidenefluororide-co-hexafluoropylene),poly(vinylidenefluororide -co-tetrafluoroethylene),poly(vinylidenefluororide-co-trifluoroethylene) and mixture of theabove-mentioned materials can be employed. Additionally, variousmaterials can be also employed as the same as the above-mentionedmaterials.

[0025] As for solid electrolyte, or gel-type electrolyte stacked on apositive electrode active layer, or a negative electrode active layer,preferable materials are made by the following processes. First, asolution comprising a macromolecular compound, an electrolyte salt, anda solvent, is impregnated into the positive electrode active material,or the negative electrode active material in order to remove thesolvent, and solidifies. The solid electrolyte, or the gel-typeelectrolyte stacked on the positive electrode active layer, or thenegative electrode active layer is impregnated into the positiveelectrode active layer or the negative electrode active layer, andsolidifies. In case of a cross-linked material, after theabove-mentioned processes, light or heat is applied to conductcross-liking to solidify.

[0026] The gel-type electrolyte is made of plasticizer including alithium salt and a matrix macromolecule in the range of equal to or morethan 2 percentage by weight and equal to or less than 3 percentage byweight. At this moment, esters, ethers, and carbonic acid esters can beemployed independently, or as one component of plasticizer.

[0027] When adjusting the gel-typed electrolyte, as for the matrixmacromolecule gelling the above-mentioned carbonic acid esters, althoughvarious macromolecules employed for forming the gel-type electrolyte,fluorine macromolecules such as poly(vinylidenefluororide),poly(vinylidenefluororide-co-hexafluoropropylene) are preferablyemployed from reduction-oxidation stability point of view.

[0028] The macromolecular electrolyte is made of the lithium salt andthe macromolecular compound, in which the lithium salt is dissolved. Asfor the macromolecular electrolyte, ether macromolecule such aspoly(ethylene oxide) and cross-linked polyethylene oxide,poly(methercrylateester), acrylates, fluorine macromolecules such aspoly(vinylidenefuluororide),poly(vinylidenefluororide-co-hexafluoropropylene) can be employedindependently, or as a mixture among the above-mentioned materials. Fromreduction-oxidation stability point of view, preferably, the fluorinemacromolecules such as poly(vinylidenefluororide) orpoly(vinylidenefluororide-co-hexafluoropropylene) can be employed.

[0029] As the lithium salt included in the gel-type electrolyte or themacromolecular solid electrolyte, a lithium salt used for typicalelectrolyte as a battery can be employed. More detail, the followingmaterials are considered: lithium chloride; lithium bromide; lithiumiodide; chloric lithium; lithium perchlorate; lithium bromate; lithiumiodate; lithium nitrate; tetrafluorolithiumborate;hexafluorophosphoriclithium; lithium acetate;bis(trifluoromethanesulfonil)imidelithium, LiA_(S)F₆, LiCF₃SO₃,LiC(SO₂CF₃)₃, LiAlCl₄, LiSiF₆. In case of the gel-type electrolyte,preferable dissolution density of the lithium salt is in the range of0.1 to 3.0 mol in plasticizer, more preferably, in the range of 0.5 to2.0 mol. Additionally, the kinds of the lithium salt, or its dissolutiondensity is not limited by the above-mentioned materials and dissolutiondensity.

[0030] As a negative electrode material, a material capable of doping orun-doping lithium is preferable. As such a material, for example, anon-graphitizing carbon material, or a graphite material is preferablyemployed. Further detail, pyrocarbons, cokes (pitch coke, needle coke,petroleum coke), graphites, glassy carbons, organic macromolecularcompound calcinated materials (materials such that phenolic resin, furanresin and the like are calcinated at proper temperature), carbon fiber,carbonaceous materials such as activated carbon can employed. As forother materials, macromolecules such as polyacetylene, polypyrrole oroxide such as SnO₂ can be employed. In a case of forming a negativeelectrode using such materials, well-known binders may be doped.

[0031] On the other hand, a positive electrode can be formed using metaloxide, metal sulfide or specific macromolecules as positive electrodeactive materials, depending on kinds of achieved batteries. Take thecase where lithium ion batteries are formed, for instance, as thepositive electrode active material, metal sulfide or metal oxide such asTiS₂, MoS2, NbSe2, V₂O₅ which includes no lithium, or lithium complexoxide mainly including LiMO₂ and the like can be employed. As fortransition metal M forming lithium complex oxide, Co, Ni, Mn arepreferable. LiCoO₂, LiNiO₂, LiNiyCol-yO₂ and the like can be consideredas specific examples of such lithium complex oxide. In the formuladescribed before, M represents equal to or more than one kind oftransition metal, x is a value satisfying in accord with a dischargestate of the battery, typically in the range of 0.05 to 1.10, y is avalue satisfying by formula: 0<y<1. These lithium complex oxide arecapable of generating high voltage, which forms the positive electrodeactive material having excellent characteristics in energy density. Aplurality of the positive electrode active materials may be used for thepositive electrode by mixing. When forming a positive electrode usingthe positive electrode active material, well-known conducting agents orbinders can be doped.

[0032] Other and further objects, features and advantages of theinvention will appear more fully from the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

[0033] These and other objects and features of the present inventionwill become clear from the following description of the preferredembodiments given with reference to the accompanying drawings, in which:

[0034] FIGS. 1A-1C are schematic views showing a method of manufacturinga lithium ion polymer battery relative to the embodiment of the presentinvention;

[0035]FIGS. 2A and 2B are schematic views showing the method ofmanufacturing the lithium ion polymer battery relative to the embodimentof the present invention;

[0036]FIG. 3 is a plain view showing a schematic structure of sealedends of package members;

[0037]FIG. 4 is a schematic view showing a main part of a manufacturingprocess conducting that the sealing members fuses and adheres to leadelectrodes without gaps.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0038] Embodiments of the invention will be described in detailhereinbelow by referring to the drawings.

[0039] FIGS. 1A-1C and 2A-2B are schematic views showing a method ofmanufacturing a lithium ion polymer secondary battery relative to anembodiment of the present invention. FIGS. 1A-1C and 2A-2B shows acondition observed in a direction shown as an arrow A in FIG. 4. FIG. 3is a view showing a two-dimensional schematic structure of sealed endsof sealing package members observed in a direction shown as an arrow Bin FIG. 4. The structure of a sealed part of the lithium ion polymersecondary battery relative to the embodiment of the present invention isalso explained hereinafter because it is embodied by the manufacturingmethod relative to the embodiment of the present invention.Additionally, in FIGS. 1A-1C, 2A-2B and detailed explanation based onthe above-mentioned drawings, for avoiding complicated drawings andexplanation, a sealing step in the method of manufacturing the lithiumion polymer secondary battery is only described in detail, and othersteps such as a forming step of a laminating structure or a cutting stepof a lead electrode, are omitted.

[0040] Sealing members 2 a and 2 b, which are made of a thermoplasticmaterial such as cast polypropylene and are not applied to heat forfusion yet, are disposed in a manner that predetermined sealed positionsof lead electrodes 1 a and 1 b are sandwiched from positions above andbeneath the positions respectively. Disposed above and beneath thesealing members 2 a and 2 b are respectively ends of package members 3 aand 3 b formed by laminating rolled aluminum foil to polypropylenefilms. Outside the ends of the package members 3 a and 3 b, strippingsheets 4 a and 4 b made of Teflon sheets are disposed (see FIG. 1A).Although illustrations are omitted, the lead electrodes 1 a and 1 b areconnected to a laminating structure, or spiral electrode units, in whicha positive electrode, a negative electrode, and a separator arelaminated and formed as a structure inside a thin and flat battery.

[0041] Following this, from the outside of the stripping sheets 4 a and4 b, in order to heat the sealing members 2 a and 2 b, the leadelectrodes 1 a and 1 b, and the ends of the package members 3 a and 3 b,heaters 6 a and 6 b are applied pressure to the predetermined positions,in which the package members 3 a and 3 b disposed the sealing members 2a and 2 b therebetween are to be sealed. As the above-mentioned moment,in a condition that temperature is not enough to fuse because heat justbegins to be applied, therefore, the sealing members 2 a and 2 b are notfused yet, gaps 5 a, 5 b, 5 c, 5 d, 5 e and the like shown FIG. 1B arelikely to exist between the sealing members (2 a and 2 b) and the leadelectrodes (1 a and 1 b) or between the sealing members (2 a and 2 b)and the package members (3 a and 3 b).

[0042] As the positions in which the ends of the package members 3 a and3 b are to close, are applied to heat, the fused sealing members 2 a and2 b can spread between the lead electrodes (1 a and 1 b) and the packagemembers (3 a and 3 b) as shown in FIG. 1C. At this moment, althoughthere is a case such that the excess sealing members 2 a and 2 b areleaked or forced out toward the outside of the package members 3 a and 3b, since the stripping sheets 4 a and 4 b made of Teflon sheet aredisposed between the sealing members (2 a and 2 b) and the heaters (6 aand 6 b ), it prevents that the forced-out sealing members 2 a and 2 bfuses and adheres on surfaces of the heaters 6 a and 6 b. Teflon sheetis a material, which prevents the fused sealing members 2 a and 2 b fromadhering.

[0043] As mentioned above, after the sealing members 2 a and 2 bcompletely fuses and spreads between the lead electrodes (1 a and 1 b)and the heaters (6 a and 6 b ) without gaps, the whole body covered withthe stripping sheets 4 a and 4 b are stripped from the heaters 6 a and 6b together with the stripping sheets 4 a and 4 b as shown FIG. 2A. Inthis time, the stripping sheets 4 a and 4 b is applied to heat underpressure with the heaters 6 a and 6 b, and even if the heaters 6 a and 6b are removed, the stripping sheets 4 a and 4 b holds a shape along withconcavo-concave shapes of the lead electrodes 1 a and 1 b or the packagemembers 3 a and 3 b, which allows the whole body to cool down until thesealing members 2 a and 2 b re-solidifies as keeping a condition thatthe package members 3 a and 3 b, or the sealing members 2 a and 2 b, thelead electrodes 1 a and 1 b are sandwiched between the stripping sheets4 a and 4 b. In connection with this, a cooling fun may be used forair-cooling, or a cooling may be conducted at room temperature. Eitherways can be selected depending ion a speed at which the sealing members2 a and 2 b re-solidifies.

[0044] After the sealing members 2 a and 2 b re-solidifies, as shown inFIG. 2B, the stripping sheets 4 a and 4 b are apart from the packagemembers 3 a and 3 b.

[0045] As described above, the package members 3 a and 3 b can becompletely sealed by means of the sealing members 2 a and 2 b, whichresults in enhancing durability of the battery and increasing itsproductivity.

[0046] Although in the sealing process relative to the above-mentionedembodiment, it is described that the sealing members 2 a and 2 b adheresto the lead electrodes 1 a and 1 b without gaps, and also adheres to thepackage members 3 a and 3 b without gaps for sealing the ends of thepackage members 3 a and 3 b by means of a single step employing theheaters 6 a and 6 b, the present invention is not limited by theembodiment. The similar technique to the previous step can be applied toa manufacturing step such that after the sealing members 2 a and 2 badheres to the lead electrodes 1 a and 1 b without gaps by means of asingle step employing the heaters 6 a and 6 b, in another step, the endsof the package members 3 a and 3 b adheres to the surfaces of thesealing members 2 a and 2 b, which seals the parts to be sealed.

[0047] In a manufacturing process employing the heaters (6 a and 6 b )and the stripping sheets 4 a and 4 b as shown in FIGS. 1A-1C and 2A-2B,without the package members 3 a and 3 b, the stripping sheets 4 a and 4b are disposed in a manner of directly contacting the sealing members 2a and 2 b, then from the outside of the stripping sheets 4 a and 4 b,heat is applied under pressure with the heaters 6 a and 6 b in orderthat the sealing members 2 a and 2 b adheres to the lead electrodes 1 aand 1 b without gaps. Following this, the ends of the package members 3a and 3 b adheres to the surfaces of the sealing members 2 a and 2 bwith thermocompression bonding or adhesion materials, thereby enablingthe ends of the package members 3 a and 3 b to be sealed.

[0048] Such a step of adhering the fused sealing members 2 a and 2 b tothe lead electrodes 1 a and 1 b can be conducted by a manufacturingapparatus whose main part is schematically shown in FIG. 4.

[0049] Initially, the lead electrodes 1 a and 1 b are supplied in amanner of unreeling from a lead roll 11, which has the belt-shaped leadelectrodes la and 1 b in a rolled way. On the other hand, the strippingsheets 4 a and 4 b are supplied from stripping sheet rolls 12 a and 12b. In addition, the stripping sheets 4 a and 4 b are accommodated in arolled shape by winding magazines 14 a and 14 b after a forced coolingstep, which will be described later.

[0050] In a heat-fusion step employing the heaters 6 a and 6 b, thesealing members 2 a and 2 b, which does not fuse yet, are provisionallypositioned on the lead electrodes 1 a and 1 b with a predeterminedinterval, are sandwiched between the heaters 6 a and 6 b with thestripping sheets 4 a and 4 b in-between. With the heaters 6 a and 6 b,from the outside of the stripping sheets 4 a and 4 b, the sealingmembers (2 a and 2 b) and the lead electrodes 1 a and 1 b are applied toheat under pressure. At this moment, the sealing members 2 a and 2 bfuses at temperature over 160°, which is fusion temperature of thesealing members 2 a and 2 b.

[0051] After the lapsed time enough for the sealing members 2 a and 2 bto fuse and completely adhere to the lead electrodes 1 a and 1 b withoutgaps, the heaters 6 a and 6 b are removed from the sealing members (2 aand 2 b) and the lead electrodes 1 a and 1 b. At this moment, thesealing members 2 a and 2 b are not stripped from the stripping sheets 4a and 4 b, and keeps a laminated state.

[0052] After this, in the forced air-cooling step employing coolingmachines 13 a and 13 b, the parts, in which the sealing members 2 a and2 b fuses and adheres to the lead electrodes 1 a and 1 b, are conveyedto the cooling machines 13 a and 13 b for conducting forced air-cooling.While the stripping sheets 4 a and 4 b are stripped from the sealingmembers 2 a and 2 b and accommodated by the winding magazines 14 a and14 b in a rolled shape after the sealing members 2 a and 2 bre-solidifies, the lead electrodes 1 a and 1 b, to which the sealingmembers 2 a and 2 b completely adhere, are rolled and accommodated by awinding magazine 15.

[0053] With the above-mentioned procedures, the sealing members 2 a and2 b can completely adhere to the lead electrodes 1 a and 1 b withoutgaps.

[0054] Although in the above-mentioned embodiment, the case that Teflonsheet is employed as the stripping sheets was described, materials,which has the following quality can be preferably employed. Materialsdoes not fuse or ablage even if heat holds temperature over the fusiontemperature of the sealing members; additionally materials has physicalstrength, which does not occur failures even if pressure is applied withthe heaters; and materials does not fuse and adhere or remain residuumto the sealing members. As the stripping sheets, sheet-like sheets canbe employed besides the above-mentioned rolled type sheets.

[0055] The sealing members are not limited by cast polypropylene asmentioned above. As for materials of the sealing members, materialshaving acceptable adhesion to the package members and the leadelectrodes, and excellent in durability, are desirable.

[0056] Although in the above-mentioned embodiment, the case that thepresent invention was applied to the lithium ion secondary battery, thepresent invention is not limited by the embodiment, it can be applied toa thin lithium ion secondary battery having the above-mentionedstructure or a manufacturing process such that the corresponding partsof the lead electrodes are sealed by the sealing members.

[0057] As mentioned above, according to the lithium ion battery and themethod of manufacturing the same of the present invention, the sealingmembers can spread between the lead electrodes and the package memberswithout gaps. Further, according to the method of manufacturing thelithium ion battery of the present invention, the sealing members canadhere to the lead electrodes without gaps. As result of this, sealingfailures caused by gaps generated between sides of the lead electrodesand the package members and gaps generated in the sides of the leadelectrodes, can be prevented, which leads to high productivity andexcellent hermeticity inside the battery covered with the packagemembers, thereby, durability of the battery increases.

[0058] More further, according to the method of manufacturing thelithium ion of the secondary battery, when heat is applied to thepackage members or the sealing members under pressure with the heaters,between the heaters and the package members, or and the sealing members,the stripping sheets made of materials such that the fused sealingmembers does not adhere, are inserted, thereby enabling the fusedsealing members to adhere to the surfaces the heaters even if the fusedsealing members are leaked, or forced out from the ends of the packagemembers, which achieves enhancement in productivity.

[0059] Still further, according to the method of manufacturing thelithium ion battery of the present invention, the sealing members cancool without disfiguring their shape even if the heaters are removedwhen the sealing members is not made in a solid state yet, thereby theheating process and the cooling process with the heaters can besimplified, further, the failure ratio caused in the covering processemploying the sealing members, can decrease, which brings productivityincrement drastically.

[0060] Obviously many modifications and variations of the presentinvention are possible in the light of the above teachings. It istherefore to be understood that within the scope of the appended claimsthe invention may be practiced otherwise than as specifically described.

What is claimed is:
 1. A nonaqueous-electrolyte secondary batterycomprising: a laminating structure, in which at least a positiveelectrode and a negative electrode are laminated; a film-like orsheet-like package member covering the laminating structure; a leadelectrode, which joints to the laminating structure and protrudes froman end of the package member toward the outside; and a sealing member,which is inserted into a gap between the end of the package member andthe lead electrode, and seals the gap by fusing a thermoplasticitymaterial.
 2. A nonaqueous-electrolyte secondary battery according toclaim 1, wherein the sheet-like package member is covered with thepackage member employing a metal laminate pack material comprisingpackage resin, a metal film, and a sealant layer, and is sealed in itsend.
 3. A nonaqueous-electrolyte secondary battery according to claim 1,wherein the positive electrode is employed lithium mix oxide whose mainbase is LiMO₂ (the transition metal M is a material selected from agroup of Co, Ni, Mn); and the negative electrode is employed anon-graphitizing carbon material or a graphite material.
 4. Anonaqueous-electrolyte secondary battery according to claim 1, wherein asolid electrolyte or gel-type electrolyte is employed.
 5. Anonaqueous-electrolyte secondary battery according to claim 4, whereinthe electrolyte is gel-type electrolyte.
 6. A nonaqueous-electrolytesecondary battery according to claim 5, wherein the gel-type electrolyteis made of a fluorine macromolecule containing an electrolyte salt and asolvent.
 7. A method of manufacturing a nonaqueous-electrolyte secondarybattery including a step of covering a laminating structure, in which atleast a positive electrode and a negative electrode are laminated, witha film-like or sheet-like package member, comprising a step of: sealinga gap between a lead electrode and an end of the package member byfusing a sealing member; whereby the sealing member made of athermoplastic material is inserted between the lead electrode and theend of the package member, wherein the lead electrode connects to thesaid laminating structure and protrudes from an end of the packagemember toward the outside.
 8. A method of manufacturing anonaqueous-electrolyte secondary battery including a step of covering alaminating structure, in which at least a positive electrode and anegative electrode are laminated, and formed in a flat shape with afilm-like or sheet-like package member, comprising a step of: sealing agap between a lead electrode and an end of the package member; wherebythe sealing member made of a thermoplastic material is inserted betweenthe end of the package member and the lead electrode whose one endconnects to the said laminating structure and the other end protrudesfrom the end of the package members toward the outside, a heater isapplied pressure at least to the end of the package member from theouter side at temperature over the fusion temperature for heating andfusing the sealing member.
 9. A nonaqueous-electrolyte secondary batteryincluding a step of covering a laminating structure, in which at least apositive electrode and a negative electrode are laminated, and formed ina flat shape with a film-like or sheet-like package member, comprising astep of: sealing a gap between a lead electrode and an end of thepackage member; whereby the sealing member made of a thermoplasticmaterial is inserted between the end of the package member and the leadelectrode whose one end connects to the said laminating structure andthe other end protrudes from the end of the package member toward theoutside, a heater is applied pressure at least to the end of the packagemember from the outer side, a stripping sheet made of a material suchthat at least its surface does not fuse and adhere to the sealingmember, is inserted, then the heater is applied to heat to the sealingmember at temperature over the fusion temperature for fusing the sealingmember.
 10. A method of manufacturing a nonaqueous-electrolyte secondarybattery included a step of covering a laminating structure laminated atleast a positive electrode and a negative electrode, and formed in aflat shape, comprising steps of: fusing a sealing member; whereby thesealing member is inserted between a lead electrode whose one endconnects to the said laminating structure and the other end of thatprotrudes from an end of the package member toward the outside, a heateris applied pressure at least to the end of the package member from theoutside, the stripping sheet made of a material such that at least itssurface does not fuse and adhere to the sealing member, is insertedbetween the heater and the package member, or the sealing member; andstripping the stripping sheet from the package member, or the sealingmember; whereby after the sealing member can spread between the leadelectrode and the package member without a gap by heating and fusing thesealing member, the stripping sheet is stripped from the heater, thenthe fused sealing member re-solidifies, and is made in a solid state.11. A nonaqueous-electrolyte secondary battery according to claim 10,wherein the sheet-like package member is covered with the package memberemploying a metal laminate pack material comprising package resin, ametal film, and a sealant layer, and sealed in its end.
 12. A method ofmanufacturing a nonaqueous-electrolyte secondary battery according toclaim 11, wherein the positive electrode is employed a transition metalchalcogen compound as an active material; and the negative electrode isemployed a material capable of doping and un-doping lithium as an activematerial.
 13. A nonaqueous-electrolyte secondary battery according toclaim 12, wherein the positive electrode is employed lithium mix oxidewhose main base is LiMO₂ (transition metal M is a material selected froma group of Co, Ni, Mn), and the negative electrode is employed anon-graphitizing carbon material, or a graphite material.
 14. A methodof manufacturing a nonaqueous-electrolyte secondary battery according toclaim 10, wherein solid electrolyte, or gel-type electrolyte isincluded.
 15. A method of manufacturing a nonaqueous-electrolytesecondary battery according to claim 14, wherein the electrolyte isgel-type electrolyte.
 16. A method of manufacturing anonaqueous-electrolyte secondary battery according to claim 15, whereinthe gel-type electrolyte made of a fluorine macromolecular materialincluded an electrolyte salt and a solvent.
 17. A method ofmanufacturing a nonaqueous-electrolyte secondary battery, comprisingsteps of: fusing the sealing member by heating at temperature over thefusion temperature of the sealing member with a heater; whereby asealing member made of a thermoplastic material is disposed in apredetermined position in a lead electrode, and a heater is appliedpressure at least to the sealing member from the outside, a strippingsheet made of a material such that at least its surface does not adhereto the sealing member, is inserted between the heater and the sealingmember; separating the stripping sheet from the package member, or thesealing member; whereby after the sealing member can spread between thelead electrode and the package member without a gap by heating andfusing the sealing member, the stripping sheet is separated from theheater, then the fused sealing member re-solidifies, and is made in asolid state.
 18. A method of manufacturing a nonaqueous-electrolytesecondary battery according to claim 17, wherein the sheet-like sealingmember is covered with the package member made of a metal laminate packmaterial comprising package resin, a metal film, and a sealant layer,and is sealed in its end.
 19. A method of manufacturing anonaqueous-electrolyte secondary battery according to claim 18, thepositive electrode is employed a transition metal chalcogen compound asan active material; the negative electrode is employed a materialcapable of doping or un-doping lithium as an active material.
 20. Amethod of manufacturing a nonaqueous-electrolyte secondary batteryaccording to claim 19, wherein the positive electrode is employedlithium complex oxide, whose main base is LiMO₂ (transition metal M is amaterial selected form a group of Co, Ni, Mn); The negative electrode isemployed a non-graphitizing material, or a graphite material.
 21. Amethod of manufacturing a nonaqueous-electrolyte secondary batteryaccording to claim 20, solid electrolyte, or gel-type electrolyte isincluded.
 22. A method of manufacturing a nonaqueous-electrolytesecondary battery according to claim 21, wherein the electrolyte is thegel-type electrolyte.
 23. A method of manufacturing anonaqueous-electrolyte secondary battery according to claim 22, thegel-type electrolyte is made of a fluorine macromolecular materialincluded an electrolyte salt and a solvent.